Sea Swirl's Submarine

by Mudpony

Rating: everyone
Tags: Cutie Mark Crusaders, Other, Adventure, Scootaloo, Sweetie Belle, Apple Bloom, My Little Pony: Friendship is Magic, Comedy
Length: 9912

Join the CMC as an attempt to interview Sea Swirl turns into an underwater adventure.

The CMC set out to interview Sea Swirl, the unicorn with dolphins for a cutie mark, for the school paper, but wind up joining her in trying out her newly constructed submarine, the Mark V.

Also, Sea Swirl is best background pony.

Published 2016-02-27 05:40:01 UTC
Last updated 2016-02-29 03:30:12 UTC

Morning Departure

"So tell me why we're doing this?" Scootaloo asked.

"We need an article for this week's issue of the Foal Free Press," Apple Bloom said.

"And Featherweight said we need to write about something different than our families," Sweetie Belle added. Scootaloo face lit up and she opened her mouth to make a suggestion, but Sweetie Belle cut her off. "And no Rainbow Dash. He was quite clear on that."

"Aww," Scootaloo said with a pout. "Stupid editor."

"Three of our last eight articles have been on Rainbow Dash. Featherweight just wants us to do something different," Apple Bloom explained.

"So I suggested we interview some other ponies in town," Sweetie Belle said, her smile beaming nearly as brightly as the soon. Scootaloo looked bored already. "And I figured we could ask them about how they got their cutie marks. It might give us some ideas about how to get ours."

"Of course, you'd have known all that if you'd been at the meeting," Apple Bloom said.

"But Dash was practicing her new move. As her number one fan, I had to be there," Scootaloo said. She looked around, taking in the buildings and the river that ran past them. "So, where exactly are we going?"

"Well, we asked Pinkie where Sea Swirl lived and, according to Pinkie, she should live in a house just past the river bend. Supposed to be a very big house."

"Oh. Who's Sea Swirl anyway?"

"She's a unicorn, like me, with a pale pink coat, two-toned purple mane," Sweetie Belle said. Scootaloo's expression was blank.

"Likes to bowl?" Apple Bloom offered. Scootaloo shook her head, still unclear as to which pony her friends were talking about. "You almost hit her with your ball when you lost control on the eighth frame?"

Still Scootaloo's expression was blank.

"Oh, I know. She's the one with the dolphins as her cutie mark," Sweetie Belle added. "You couldn't have missed that. She's the only one in town with a cutie mark like that, which is why we thought she'd be such a good choice."

"You mean the one with the two fish swimming in a circle?" Scootaloo asked.

"Dolphins aren't fish," Sweetie Belle said.

"Are too. They live in the water and have flippers, don't they? I remember Miss Cheerilee saying those are fishie things," Scootaloo retorted.

"Are not."

"Are too."

Before Sweetie Belle could further the argument, Apple Bloom pointed to a large house just ahead. "That must be it," she said.

Pinkie had said the house was big, but Apple Bloom had not imagined it would be that big. It was easily three times bigger than any of the surrounding houses, which were no slouches in the size department. Looking more carefully, she could see that the house seemed to be made up of two parts. One part looked to be an actual house, and that was about the same size as the other houses in the neighborhood. The rest of it was more like her family's barn, if her family's barn had a large landscape painting of the beach painted upon it.

"Sure is big," Scootaloo said. "And uniquely painted."

"I bet it's bigger than Diamond Tiara's house," Sweetie Belle said, her eyes wide. Then she started to grin. "I'm so going to tell her that the next time she bothers us." She took another look at the house and whistled. "Sea Swirl must be rich or something if she can afford to live in that."

"Something else to ask her, Ah reckon. Come on, girls. Let's go," Apple Bloom said, walking up to the front door. Like the one for the Golden Oak Library, the door was split into two parts, with the top and bottom able to be opened separately. She grabbed hold of the octopus themed door knocker and knocked loudly.

They could hear someone calling, "Just a minute," from inside, and the top half of the door flew open, nearly knocking the Crusaders silly. Luckily, riding around with Scootaloo had taught all of them the importance of ducking quickly to avoid serious head injuries.

Sea Swirl's head popped out, looked around, from side to side. "Hmm," she said, confused. "I could have sworn I heard somepony knocking."

"Down here," Apple Bloom said, from where she huddled on the ground.

"Oh, what are you doing down there? Crawling on the ground is a rather strange way for ponies to travel. Are you perchance a new breed of pony, like the crystal ones?" Without waiting for a response, she slapped the magnifying glass attached to a headband into place. In rapid succession, she inspected them, paying particular attention to Sweetie Belle's horn, Scootaloo's wings, and Apple Bloom's hooves. With a disappointing sigh, she set them back down and slid the magnifying glass upwards. "Nope, you seem to be nothing out of the ordinary."

"Actually, we are here to—" Apple Bloom started.

"Oh, I know why you must be here," Sea Swirl said. "What's-his-name sent you, right?"

"What's-his-name? You mean Featherweight?" Scootaloo said.

"Featherweight... That could have been his name, I suppose." Sea Swirl rubbed her hoof along her jaw, trying to remember. "I'm sorry. I suppose I should explain. I'm terrible with names much of the time. If I can see a cutie mark, I do fine, but usually without that, poof, gone. Silly, I know. I can remember the species name of hundreds of types of starfish, yet I have trouble remembering the name of a single pony." She laughed awkwardly.

"Anyway, so Featherweight sent you." She looked them over again. "You do look a bit young, but I did ask for small ponies."

"Ah'm a big pony!" Apple Bloom protested.

"Of course you are. I'm sure..." Sea Swirl's eyes shifted as she tried to remember the name, before she shrugged and decided these must be the ponies she was waiting for. "I suppose he wouldn't have sent you if you weren't capable." She opened the bottom half of the door and invited the fillies in.

The crusaders looked at each other, wondering if this pony might not be a little crazy. Finally, Apple Bloom shrugged and started to follow inside. "She's not much worse than Twilight."

"Guess science makes ponies a bit strange," Sweetie Belle said, following along.

"Maybe somepony should do a study on that," Apple Bloom suggested.

"Could you trust the results though? It being science and all, I mean?" Sweetie Belle asked.

"She actually kind of reminds me of your sister when she has a new fashion idea, with the prodding and the poking and the measuring," Scootaloo said.

"She does not do that!" Sweetie Belle protested, causing Scootaloo to stop and look at her. "Okay, maybe she does a little." Scootaloo's look continued. "Okay, a lot," Sweetie Belle conceded. Scootaloo grinned and started moving again. "Hmm... I bet other ponies probably think the same thing about us and our crusading ideas."

"Ah guess all ponies can get a bit silly when it is about something that gets them really excited," Apple Bloom said. "Why Ah bet— Oh wow."

All three crusaders stopped and gazed around the room they had just entered in wonder. Aquariums lined the walls, some built right into them. Near each one were several plaques. But what had the attention of the crusaders was the content of the tanks. Each teemed with brightly colored fish swimming amidst coral and seaweed, and several were the size of a full-grown manticore. The crusaders rushed from tank to tank, gawking at the spectacle.

Sea Swirl nodded knowingly. "Beautiful, aren't they? And these hardly do the reality justice. You should see some of the actual locations. Reefs going on for as far as the eye can see. I love the water and all things aquatic. I'm planning to open this place as an aquarium, once I have enough specimens and all my paperwork in order with city hall."

"An aquarium? Is that why you painted the outside of the house that way?" Sweetie Belle asked, tearing her eyes away from the aquariums.

"Oh, no. That's just because I find it pretty. Reminds me of the beach in Acucoltco. Spent a great summer there studying swordfish. Shame my neighbors don't agree though. They're all eyesore this and eyesore that. No eye for beauty in a single one of them."

"Well, I like it," Sweetie Belle said.

Sea Swirl smiled. "Of course you do. What's not to like? But my neighbors, they complain. It's what they seem to love doing most in life. Painting this, explosions that, don't hit stuff with hammers late at night. It never stops."

"Explosions?" Scootaloo asked.

"Oh yes. 'Your explosions are too loud,' they say. Ha! You try to get explosions to be quiet. I mean, you can ask them beforehand, 'Please be quiet,' but do they listen? Nope. Kaboom! As loud as they can be. Maybe even louder, just because you asked them to be quiet. Quite ornery, explosions. Let me tell you, if an explosion ever wants to blow you up, I advise you run away, fast as you can. Else you could get hurt, big time."

"But why are you blowing stuff up?"

"Ah, now that's a good question. And I've got a good answer. I study things underwater, see? Now, you might not know this, but underwater, if you go down far enough, it is dark. So how can I see where I'm going? No can do. But then I figured maybe I could hear where I was going instead." She gestured up to a red fruit bat than hung from a rafter. With a squeak, the bat flew down, making the crusaders jerk aside reflexively, and clung to Sea Swirl's neck. "It was actually Fruity that gave me the idea. Bats can fly safely in the dark because they use sound, use echoes, to know where things are. And I thought, 'That's a good idea, Sea Swirl. All you need is a very loud sound.' And so explosions.

"Didn't work so well though. Never did solve the hearing side of things. Tried out the sound generation system though. That's how I lost the Mark II. Good thing I tried it in shallow water, let me tell you. Otherwise I wouldn't be here and we wouldn't be taking the Mark V for a spin."

"Mark what now?" Apple Bloom asked.

Sea Swirl seemed to ignore the question as she pushed open a pair of double doors. The crusaders followed and found themselves in a barely lit room. There was something large in the middle of the room, but they couldn't make out what it was. Sea Swirl felt along the wall and flipped a large switch. Row by row, lights flickered to life in the ceiling.

The crusaders' jaws dropped open at the sight before them. Held up by thick chains from above and supported by large wooden blocks from underneath was a giant metallic fish shaped contraption. The light reflected off the grey metal hull, lined with brass and other metals, while crystal windows lined the side. A pair of larger windows were on the front, looking like eyes. Completing the fish look was the mouth-like opening beneath the 'eyes'.

"Behold, the Mark V," Sea Swirl said proudly. "Fins for stabilization and lateral movement. Tail fin for forward drive. The mouth contains the first functioning prototype of my FRUBAR device, that's short for Fruit Bat Acoustic Ranging device. The view ports are made from the strongest crystal, just picked them up from the Crystal Empire. He'll hold a crew of four, plus a fruit bat, and should have a safe diving depth of just under three hundred feet."

Sea Swirl looked over at the awestruck crusaders, grinning. "So, what do you think? Up for being his crew? Ready to take him for a spin?"

"You want us to crew him?" Sweetie Belle asked.

"Well, of course. That is why you are here, right?" Sea Swirl asked.

"Hold on just a second while we talk it over," Apple Bloom said.

The three crusaders huddled together. The fact that they were apparently not who Sea Swirl was expecting fought against the opportunity to try something brand new. The possibility that they might not be able to do what was expected against the certainty that they would not know for sure that they could not unless they tried. There was also the question of whether or not it was safe.

Sweetie Belle popped up out of the huddle. "Is it safe?" she asked.

"Oh, most certainly," Sea Swirl answered. "Well, as safe as any such venture can be. I mean, a few of the earlier Marks sank, but this one incorporates everything I've learned from the others. That's why I got the windows from the Crystal Empire. They are much stronger than the ones I used in the Mark IV. I certainly wouldn't be trying it if there wasn't at least an above seventy percent chance of not sinking."

Sweetie Belle nodded and ducked back into the huddle. The discussion continued, but the tide was turning in favor of going.

"What about the explosions?" Scootaloo asked.

"Explosion free since the Mark II. No, the FRUBAR system doesn't rely on blowing up a single thing. Instead, I've trained Fruity here" —she lovingly rubbed the side of the bat's head— "to emit sounds through a special microphone plate and listen through some hydrophones, my own invention, then signal the results with his wings."

Scootaloo nodded, looking slightly disappointed, and returned to the huddle. The thought of seeing things very few ponies had ever seen before was compelling, and how awesome of a story this would make for the paper? Most importantly of all, of course, was the possibility that this was the way to get their cutie marks. How often would they get a chance to try this sort of thing? One possible objection remained though.

Apple Bloom popped up. "How long will the trip take?" she asked, worried, as were the others, about having to explain a long absence to their families.

"Oh, this first trip is just a shakedown cruise. We'll follow the river to Deepbottom Lake, dive down, then return. So about three hours, barring a major storm leaving us stranded on a tropical island," Sea Swirl said. At the Scootaloo's worried expression, she continued, "That was just a joke. There's no tropical islands near here. Nope, we're far more likely to sink to the bottom, never to be seen again."

Apple Bloom ducked back into the huddle. The three fillies looked at each other, then nodded. They were in. The possibility that their cutie marks awaited below the surface of the water was too strong of a lure to ignore.

"We'll do it!" all three exclaimed.

Hostile Waters

"And here we go: Three sailor suits that should fit," Sea Swirl said as she levitated the three uniforms over to the crusaders.

It had taken Sea Swirl some time to find them, but she had insisted that they were necessary. "Anything worth doing is worth doing right," she had said, which made sense to Apple Bloom, as she had heard it often enough from Applejack, and to Sweetie Belle, who had often heard a slight variation, with "in style" replacing the "right" from her sister. Sea Swirl herself wore a dark blue coat with a dual row of buttons and golden epaulets. A bright red sash and admiral's hat completed the look.

Sea Swirl gave herself a once over in a mirror, then nodded approvingly. She gave a sharp whistle, and Fruity swooped down, latching onto the sash. "Someday, I'll manage to train him to perch on my shoulder, but so far, he resists all my efforts. Don't you, Tootie-Fruity?" she said, as she rubbed the bat's head.

"Anyway, now that we're all properly dressed, let's get the Mark V in the water. Then we can load up the supplies," Sea Swirl said. She pointed to a pair of large wheels. "Horn, bow, turn those to right." Due to her name related memory issues and the lack of cutie marks on the crusaders, Sea Swirl had resorted to calling each crusader by a distinguishing feature. Sweetie Belle had become 'horn', Apple Bloom 'bow', and Scootaloo was 'wings'.

The two fillies strained against the wheels, slowly turning them, which in turn reeled in the chains, lifting the Mark V slightly off the blocks, swinging gently.

"Okay, wings. Help me get these blocks out of the way," Sea Swirl commanded. Scootaloo grunted and groaned while she manipulated one of the large blocks to the side of the room, while Sea Swirl moved the other three. The blocks moved away, Sea Swirl used her magic to pull a lever. With a loud clang, the metal plates on the floor dropped open, revealing a bay filled with water underneath.

"Okay, now lower him down! Slowly now!" Sea Swirl called out.

"Aye-aye, Captain!" Sweetie Belle called back, as she and Apple Bloom released the brakes and slowly lowered the Mark V. "This... is... hard... work," Sweetie Belle gasped.

"Easy compared... to... apple bucking," Apple Bloom gasped back.

But with the last word, her grip slipped and the wheel spun freely. As the Mark V tilted and the extra weight shifted onto the chain Sweetie Belle was controlling, she cried out and leaped backwards. The chains whirred through their pulleys, and the Mark V hit the water with a thunderous crash, sending water splashing over the edge. Both fillies rushed to the edge, worried expressions on their faces.

"We're so sorry, Miss Sea Swirl," Apple Bloom apologized.

"That wasn't slowly, guys" Scootaloo said.

"Like you know what slow is. We've seen how you drive through town," Apple Bloom replied, sticking her tongue out at Scootaloo.

"We've experienced how you drive through town," Sweetie Belle said.

"Well, I do know what it is, and that definitely wasn't it. Next time, do try to take it a bit slower," Sea Swirl said, as the fillies nodded apologetically in return. "Wait here." Her horn glowed and she dropped the gangplank into place. Quickly, she strode down to the Mark V and checked what she could from the outside, before entering a hatch on top. A couple of minutes later, she climbed back out and gave the hatch an affectionate tap.

"He's a stout boat, no leaks, so let's get the supplies on board." Sea Swirl climbed back up the gangplank and pointed out several boxes. "We'll want the box of fruit, that barrel of drinking water, the rum, the blue one over there, the hydra repellent, that crate of bread, and those charts." She herself levitated a small camera case. Turning to the fillies, she said, "Well, get going. Those things aren't going to load themselves."

"Could be worse," Sweetie Belle said, as she and Scootaloo struggled to move the water barrel.

"Yeah, could be going camping with Rarity," Apple Bloom said, causing all three fillies to giggle.

The joke restored the crusaders' spirits and with some teamwork and only a few minor mishaps, they got the requested items stowed aboard in the locations Sea Swirl wanted them. Fruit hung in nets dangling from the ceiling, the charts were stored in a small cabinet, and so on. What was already a limited space became even more crowded with all the goods stowed aboard.

Sea Swirl looked it all over and nodded approvingly. "Okay then, let's get you three to your posts, and we'll be good to go."

Scootaloo looked around the inside of the submarine and tentatively raised a hoof in the air.

"Yes?" Sea Swirl asked.

"I don't see any posts in here. Or even poles. Are they on the outside of ship?" Scootaloo asked.

"Posts means where we'll be working, silly," Sweetie Belle said.

"That's correct," Sea Swirl said. "Also, this is a boat, not a ship. I know because I get terribly seasick on ships, but not on boats, which is sort of strange, what with boats being smaller than ships and all, but that's how it is. There's no way I want to get sick inside my submarine, so I've decreed that it is a boat. Smart way to avoid the problem, huh?"

"How does that even make sense?" Apple Bloom asked. Her fellow crusaders shrugged in reply.

"Just roll with it," suggested Scootaloo.

"And speaking of rolling, you must be the propulsion specialist, right?" Sea Swirl asked Scootaloo, who looked blankly back at her. "Well, of course you must be. Fact: I built the propulsion unit to be controlled by a pegasus. Fact: I specified I needed a pegasus for that job. Fact: you are the only pegasus. Conclusion: you must be the propulsion engineer."

"Um... okay," Scootaloo said.

"Excellent! Let's get you situated then. Stand here and hold out your wings please," Sea Swirl asked.

Scootaloo stood where Sea Swirl indicated and tentatively held out her wings. Metal tubes and fixtures attached themselves from above, below, and both side, fastened by straps. Padding covered them, Scootaloo noted thankfully. Sea Swirl spend a bit of time fussing with them, adjusting them to fit properly and comfortably.

"There. All done. Running on the treadmill will move the tail, driving us forward or backward. Your wings control the flippers, allowing you to turn the boat. And you can move this lever with your mouth to switch between ahead, full speed ahead, and reverse. Pretty good design, huh?" Sea Swirl asked. "I worked on it for a whole twenty minutes. Should be just like I imagine flying would be." She looked at Scootaloo's wings for a second. "You can fly right?"

"Um, yeah. Of course! I'm a pegasus. All pegasi fly," Scootaloo said, with her best convincing look on her face. Behind Sea Swirl, her two friends waited anxiously to see if their captain would see through it.

"Groovy! Then you'll find it easy as memorizing the periodic table of elements," Sea Swirl said. Apple Bloom and Sweetie Belle sighed in relief, then gave each other a quick high hoof. "Now, who is going to man the FRUBAR device?"

"Does that mean working with Fruity?" Apple Bloom asked.

"Yes."

"Dibs!" called Sweetie Belle, waving one forehoof enthusiastically while shoving the other into Apple Bloom's mouth.

"Okay, horn, you'll be sitting here," Sea Swirl said, pointing to a chair at the front of the boat.

"Dafftp nauff faium!" Apple Bloom mumbled. She pulled Sweetie's hoof out of her mouth. "Ah wanted tah do that!"

Sweetie Belle stuck her tongue out at Apple Bloom. "You snooze, you lose," she said, sliding into the seat. She listened intently as Sea Swirl rattled off things about how the FRUBAR device worked.

"And you'll be reading the depth gauge as well, whenever we change depth. Just call out our depth every ten feet," Sea Swirl finished. "Got all that?"

Sweetie shook her head.

"Excellent! You'll do great," Sea Swirl said, ignoring Sweetie's reply and turning to Apple Bloom. "And that leaves you, Bow. You'll be chief engineer and dive officer." In rapid order, she proceeded to explain how to work the dive controls, as well as Apple Bloom's duties as chief engineer. "And that's all there is to it. Easy as washing cats."

Sea Swirl floated a clipboard over, marking a few boxes with check marks. "Okay, now let's get going. For science!"

"For science!" the crusaders dutifully cheered.

"Science sure is boring," Apple Bloom said, stifling a yawn. "Ah'm almost fallin' asleep."

The crusaders' excitement of leaving the dock had faded with the reality of the slow cruise down the river toward the lake. Sea Swirl, well, for her it was a different story. She dashed around the ship, from port to port, peering out into the water. She jotted down notes and chattered non-stop about what she saw, mostly ignoring the conversations of the crusaders and being ignored by them in return.

"At least you got it easy," Scootaloo replied, wiping some perspiration away. "All you have to do is sit. Me, I feel like I've been scooting uphill all day. Except with somepony giving directions to me in a foreign language."

"Not mah fault you don't know your aft end from your bow," Apple Bloom said. "Though, to be honest, repeating that stuff is all that's keeping me awake."

"I'm having fun," Sweetie Belle said, as she scratched Fruity behind his ear, earning a satisfied croon from the fruit bat. Both of her fellow crusaders glared at her.

"Don't worry, maties," Sea Swirl said encouragingly, taking a quick break from what she writing in her notebook. "The lake is just ahead, and then we can take him under! Ah, the wonders we'll see. Why, we'll be the first ponies to go down this deep and probably return. Ooh, that's a big one." She rushed to the starboard bow port and started to write furiously. "Sorry about that. Just very rare to see one of those anywhere but deep in the lake." She set down her notepad. "Wonder what had him so riled up? Oh well, suppose it doesn't really matter right at this moment."

"Ten degrees starboard," Sea Swirl ordered.

"Bit to the right," Apple Bloom translated for Scootaloo's benefit. Scootaloo nodded, adjusting her wings, and the boat turned to its new heading.

"Well, I suppose it is time to take him under. Dive officer, batten the hatch," Sea Swirl ordered.

"Roger!" Apple Bloom said, happy to have something to do. She clambered up the ladder and slammed the hatch shut, spinning the handle to seal it tight. "Hatch secure, captain."

"Okay, take him down. Thirty feet."

"Aye-aye, thirty feet!" Apple Bloom spun some levers and the boat began to submerge.

"Ten feet. Twenty feet. And thirty!" Sweetie Belle said, as Apple Bloom quickly shut the valves.

"Holding steady, Captain," Apple Bloom reported.

"Let's keep him at this depth for a while and see how it goes." Sea Swirl checked a few gauges. Nodding, she said, "Looking good. And speaking of looking, what do you say we put those windows to use?"

"Alright!" the three fillies cheered.

Sea Swirl rested her hoof on Scootaloo, putting a stop to her attempts to unbuckle herself. "Not you, wings. We need propulsion."

"Bah. This job just keeps getting worse."

"Look, an octopus!" Sweetie Belle said, holding Fruity up to the window so he could see as well.

"Wow, that one sure has lots of arms," Apple Bloom said.

"That's because that isn't an octopus," Sea Swirl said. "That's a dodecapus. See? It has twelve tentacles."

"I wanna see," Scootaloo said, straining against the straps. The movement threw her off balance, and she instinctively threw up one of her wings. The Mark V rolled to the left in response, sending the dodecapus racing off in a cloud of ink.

"Aww. You scared it off," Sweetie Belle said.

"I just wanted to see it," Scootaloo muttered. "This job sucks."

"Don't worry. There's plenty more to see, and surely some of it will be where you can see it," Sea Swirl reassured Scootaloo. "Let's go deeper. Dive Officer, take him down to one hundred and fifty feet."

"Aye-aye, Captain," Apple Bloom said, settling back into her station. The bow of the submarine shifted downwards, and the submarine dropped down to the desired depth.

"Okay, now let's test the active FRUBAR. Ready, horn?"

"Just a sec," Sweetie Belle said, as she worked on fastening Fruity into the device. The bat nipped at her leg when she got one padded clamp in the wrong location, but otherwise sat still. Once the headphones were in place, Sweetie Belle gave the bat one final checkover and nodded her approval. "Okay, Captain, ready!"

"Let's try out a full spectrum ping!" Sea Swirl said. "Intensity setting eleven. That's the red knob, the one by your right hoof. And turn that blue to three-sixty. Flip the lever to full angle."

"Why's it called a ping?" Sweetie Belle asked, as she made the necessary adjustments..

"Tell Fruity to ping and you'll see," Sea Swirl said. "Well, actually hear, I guess. Though I did have an aunt who could see sounds. She spent her life trying to turn the stain glass murals in Canterlot's palace into operas. They weren't very popular, I'm afraid, though she insisted the sounds were colored just right. But I digress, we're here to science. Give me a ping!"

"Fruity, ping!"

The bat squeaked into the microphone. The boat vibrated slightly as the amplification system on the outside of the boat projected the squeak out into the water. Some of the sound could be heard inside. It was weirdly metallic sounding, sort of like a metal rod being struck by a ball peen hammer, but not quite. With a shrug, Sweetie Belle decided that 'ping' was as good of a name for the sound as any.

"See how he's sweeping both his wings wide and flat, not point in any particular direction? That means there's nothing big nearby. No obstacles to avoid, in other words. If he'd heard something, he'd have flapped his wings and pointed in the appropriate direction. All quite ingenious, if I do say so myself. Now, adjust the intensity down to three. We wouldn't want to scare everything off with a huge racket, now would we? And turn the blue one to zero degrees. Lever down to three. And ping!"

"Aye-aye, Captain. Fruity, ping!"

This time, the ping was barely audible inside the boat. Fruity held up his wings out, as if looking for a hug. "That's the angle we pinged," Sea Swirl explained. Next, Fruity shifted the wings flat, and crossed them back and forth. "And that means there's nothing there."

Sea Swirl rested her hoof on Sweetie's shoulder. "Now, horn, you should be able to handle it, right? Just slowly adjust the blue knob to ping in different directions, and let me know if FRUBAR reports anything of interest. And reward him with a bit of fruit from time to time. Easy as eating pancakes."

"Okay, Captain," Sweetie Belle said, earning a soft squeak from Fruity as she stopped rubbing his ears. "Let's do this, Fruity!"

Apple Bloom was definitely wrong, she decided. Science wasn't boring at all. She smiled contentedly as Fruity took a piece of fruit from her hooves and gulped it down.

Sweetie Belle changed her mind. Science was boring after all. With one hoof she supported her head, while the other mechanically alternated between adjusting the dial and feeding Fruity the occasional piece of fruit every ten or so pings. Even Apple Bloom, who had nothing to do but look out the windows and relay the occasional order, had gotten bored, she noted. There just wasn't much interesting about brown fish, grey fish, and underwater plants that looked slimier than Flim and Flam.

She held up the next fruit offering, a piece a pear, waiting for the almost ticklish contact with Fruity's tongue as he took the offering. When it didn't come, she broke out of her near catatonic state.

"Um, Captain Sea Swirl? What's it mean when Fruity wraps his wings completely around him and tries to scrunch up into a little ball, while shivering and mewling in terror?" Sweetie Belle asked.

Sea Swirl's notebook and pencil clattered to the floor as her eyes shot wide. She rushed from port to port, staring out into the water. Complete her check of all the ports, she breathed a sigh of relief. "Probably nothing. Just a false alarm. Absolutely nothing to worry about."

"Ah, good," said Scootaloo. "I thought it might have something to do with this large eye looking at me."

"Ah got one looking at me too," Apple Bloom said.

"Me three! And four!" Sweetie Belle added, pointing at both forward view ports.

Sea Swirl's head swung from port to port. "H-h-hydra!" Sea Swirl shouted, running around the boat in a panic. It was an impressive feat, given the small size of the boat and how cluttered it was inside, but she managed it somehow.

"Hydra?" all the fillies said in alarm.

Sea Swirl slid to a stop. "Gigas Lacus Hydracus. Native to lakes throughout the continent. Extremely territorial during mating season," she calmly lectured, her panic from moments before forgotten.

One of the heads stared in through port, then pulled away, before slamming full force against the submarine. Objects flew from their shelves, the ponies stumbled, trying to stay afoot, and the hull creaked ominously as the Mark V shook from the collision. A second later, the submarine shook again, as the hydra slammed another head against the intruder.

"Let me guess: It's mating season?" Apple Bloom asked, bracing herself against the hull.

Sea Swirl nodded, as the Mark V shook from another impact. "Oh-oh." Again the hull creaked, and this time, a stream of water started shooting out of a pipe. "Oh boy, this is bad. He wasn't designed to take this sort of a pounding! We've got to get out of here. Flank speed!" Sea Swirl shouted.

"Go fast!" Apple Bloom dutifully translated.

"I figured that one out for myself," Scootaloo yelled, as she shifted to the highest gear and started running on the treadmill as fast as she could. The submarine lurched forward, slowly at first, but rapidly picking up speed as its tail fin thrashed back and forth.

"We're losing him! I think he's losing interest!" Apple Bloom shouted, as she glanced out one of the rear ports, before returning to her work fixing the leaky pipe.

Sea Swirl shouted. "Keep going! Horn, FRUBAR reading! We don't want to run into anything. Bow, keep lookout."

"Okay," Sweetie Belle squeaked, quickly adjusting the controls and holding Fruity up to the microphone. It took a bit of coaxing to calm the fruit bat enough so he could do his job, but she managed it. "All clear ahead!"

"He's back!" Apple Bloom shouted, her head now pressed against one of the rearward facing view ports.

"All hooves, brace for impact!" Sea Swirl commanded.

The boat shuddered as the hydra smashed into it. Another pipe sprung, dousing Sweetie Belle and Fruity in an icy spray of water. The fearful fruit bat tried to break free, screeching loudly, Sweetie Belle's previous efforts undone. Almost immediately, the hull reverberated from another impact, and then another, sending Apple Bloom and Sea Swirl flying, while even more water entered the boat through new leaks.

"More speed," Sea Swirl ordered.

"Can't, Captain! Something's jammed. Propulsion is down!" Scootaloo shouted, as the bat screeched again. Another hard blow slammed into the submarine.

"The sound! The soundy thingy is making it angry!" Scootaloo yelled. "Shut it off!" Sweetie Belle quickly flipped the power switch.

Sea Swirl scrambled to her feet and fished for her notebook off the floor. "Horseapples!" she cursed. "The paper is all wet. How can I take notes now?"

"Can we worry about staying alive first and take notes later?" Sweetie Belle yelled.

"But how can I remember to add hydra repellent to the next model if I don't write it down?" Sea Swirl asked, as another blow hit home. "Oh, and probably some sort of passive FRUBAR might be a good idea, at least during hydra mating season."

"Hydra repellent! We loaded that, didn't we? How do we use it?" Apple Bloom asked.

"We did? Oh. That was smart of me." The boat shuddered under another impact. "Now let's see, how would a genius such as myself release hydra repellent. It'd have to be a button, located just about… there." Sea Swirl pointed to a panel near Apple Bloom. "The big red button. Or maybe the green one. Definitely one of the two. Most likely."

Apple Bloom slammed hooves down on both buttons. The submarine lurched as two compartment dropped off its sides, tinting the water around the submarine green. The hydra slammed into the boat once more, and then it stopped.

"It's backing off," Sweetie Belle called, looking out one of the forward ports. "I think it's swimming away. Yes, it's leaving!"

The crusaders whooped and cheered with joy. Sea Swirl did not join in, instead scanning the interior of the boat.

"Quiet. We're not out of this yet," Sea Swirl said. "Horn, check our depth! Chief, get those leaks plugged." She glanced at Scootaloo, who was busy working to extract herself from the harnesses that tied her to the propulsion system.

"Two hundred feet!" Sweetie Belle reported. "No, wait, two-ten." She stared at the gauge. "Two-twenty." With each report, her voice got quieter. "Two-thirty."

"Fix those leaks, engineering!" Sea Swirl ordered. She herself rushed to one of the depth control pumps and began pumping.

"Two-forty," Sweetie Belle whispered. "Two-fifty. It's not slowing. We're not slowing." Her eyes were wide with fear. "Two-sixty."

With a curse, Sea Swirl quit using the pumps and moved to assist Apple Bloom with fixing the leaks, quickly joined by Scootaloo, who had worked her way free.

"Two-seventy."

The hull screeched and popped ominously.

"What was the max depth on this here coffin again?" Apple Bloom shouted, as she wrestled with a pipe wrench.

"Two-eighty."

"Just under three hundred. In theory," Sea Swirl replied, pounding a seal home on another leak.

"Two-nighty."

"Don't worry, he'll hold together," Sea Swirl said, doing her best to reassure her crew.

A particular loud pop sounded right as Sweetie announced that they had hit three hundred.

"Come on, laddie, hold together," Sea Swirl pleaded, gently stroking the side of her boat with a hoof.

"Three-ten."

The crew collectively held their breaths and prayed to the princesses.

"Three-twenty."

The Mark V shook as it hit bottom, the lights inside flickering, and settled.

"Steady at three hundred and twenty-five," Sweetie Belle reported, her feet standing in water. Water that continued to rise.

Grey Laddie Down

"Pump faster!" Sea Swirl bellowed. "Fix stuff! Plug leaks! Go, crew!"

"I'm... pumping as... fast as... I can!" Sweetie Belle replied, gasping for breath as she moved the handle on the pump back and forth as fast as she could.

Apple Bloom moved a beam into position. "Just a little longer, Sweetie. We've almost got it."

With several blows of a hammer, Scootaloo wedged the beam into place, and another stream of water stopped.

"Good job, Scootaloo," Apple Bloom said. "Now to get that last one under control…"

The last one, however, was ornier than a dieting manticore at an all you can eat sheep dip. It had resisted all efforts to bring it under control. Water still sprayed into the submarine despite the use of a wood, tar, and glue. It had even resisted Sweetie Belle's most earnest pleading.

Apple Bloom chewed on her lip as she stared at the leak. "The harder woods didn't work. Neither did softer ones. We need..." Her eyes scanned the interior, shifting rapidly as one possibility after another was analyzed and discarded, until she found herself staring at the drive mechanism. "That."

"The drive band?" Sea Swirl asked, following Apple Bloom's gaze.

"Won't we need that to get home?" Scootaloo asked.

"Not if we drown first," Apple Bloom said.

She hopped forward and began taking the machinery apart. Scootaloo stood frozen for a second, then joined in. With the two fillies, the work went quickly, and it wasn't long before Apple Bloom triumphantly held up the band.

"Okay, Scootaloo, remove the bracing.... Now I'll put this in place… and put the bracing back! Hammer it down!"

With repeated hammer blows, the steady spray of water was quickly reduced to a trickle. With the threat of imminent drowning removed, Scootaloo moved over to help Sweetie Belle with the pumps, and it wasn't long before most of the water was out of the submarine.

Apple Bloom looked over at the scattered parts that had been Scootaloo's station. "Now all we got to do is fix that."

Scootaloo whistled at the mess. "At least we got plenty of time."

"Yeah, about that…" Sea Swirl said.

"What?" all three fillies said.

"Well, see, we sort of need oxygen to stay alive, and we can't exactly open up a hatch down here to let in some fresh air."

Sweetie Belle leaned on handle of the pump. "You mean there's no way to refresh the air?"

"What? Of course there's a way. I built in an emergency air renewal system. It should be in that cabinet above your head, wings."

Scootaloo popped the latch on the small cabinet. Small paper packets rained down upon her head. Some stayed there, while others slipped off and fell to the grating or water below.

Apple Bloom picked one up and opened it. "Seeds? Your emergency air renewal system is seeds?"

"Yup. Nature's oxygen refresher system," Sea Swirl said. "We'll just plant them and boom, a near infinite supply of oxygen."

Apple Bloom arched one eyebrow. "Plant them in what exactly? And even if we had something to grow them in, just how fast did you expect them to grow?"

"Oh. Well, I guess it is a good thing I wasn't born an earth pony then. On to Plan B. Everypony… try to breath as little as possible." Sea Swirl took a breath so big her cheeks puffed out, and held her breath. Her face started to turn blue beneath her coat. With a gasp, she exhaled. "Okay, that won't work."

Scootaloo shook her head. "Just how much air do we have?"

Sea Swirl used her magic to float over her notepad and pencil. "Let me see. Carry the four. Divide by the circumference of the moon. Multiply by i to the power of four. And that means… two days."

Scootaloo breathed out a sigh of relief. "Two days isn't so bad. We should be able to figure out something by then."

"Give or take three days," Sea Swirl added.

"So we could run out any time then?" Sweetie Belle asked.

Sea Swirl nodded, and tore off several sheets of paper from her notebook, floating one to each filly. "If you feel like you can't breath, be sure to write down all your observations."

Apple Bloom just shook her head and turned her attention to the scattered parts laying at her hooves. "Well, Ah reckon I'd best get this drivetrain fixed as quickly as possible then. Ah don't suppose there's any spare parts?"

"Well, remember when I said it was the green or the red button for the hydra repellent?"

Apple Bloom nodded.

"Whichever one it was, the other one dumped the spare parts."

"Oh, great. Real good design there," Scootaloo said.

"You really think so?" Sea Swirl asked. "I was kind of worried that it could result in a mix up."

"Well, we're at the bottom of the lake, with no hope of rescue, and we can't fix the stupid boat because the spare parts got dumped, not that we could have reached them anyway, because they were on the outside of the boat!" Scootaloo said. "So no, I don't really think so."

"Okay, then I'll just add a note to do it different on the Mark VI," Sea Swirl said.

"What's the point in doing that right now anyway?" Sweetie Belle asked.

"Nothing else to do until that one there" —Sea Swirl pointed at Apple Bloom— "gets the drive fixed. So I might as well science."

"She's got a point, guys," Scootaloo said.

"About science?" Sweetie Belle asked.

"Not about that. About not having anything else to do until Apple Bloom thinks of a way for us to get out of here."

"Wait an apple pickin' minute. Why do Ah have to fix it by myself?" Apple Bloom asked.

"Well, you are the chief engineer," Scootaloo said. "My job's running on the treadmill. Your job's making sure the treadmill works. Besides, having two ponies in there just means they'd get in each other's way."

"And you're usually pretty good at fixing stuff," Sweetie Belle said.

"Ah'm not sure if Ah can fix this though," Apple Bloom said, looking forlornly at the broken drive system.

"You will," Sweetie Belle said hopefully. "I just know you wouldn't let us down."

"Of course she will. It's her job as chief engineer," Sea Swirl said, without looking up from her sketching. "Besides, I'd have to fire her if she couldn't fix it, and we wouldn't want that, now, would we?"

"Right… but what I was thinking is that, we should do our interview for the paper while we wait," Scootaloo said. "If that's alright, Captain?"

"An interview? I love those! Well, except when they're by psychologists." Sea Swirl's body gave a shudder. "Not a real science that. Just a bunch of mumbo-jumbo."

"Good thinking, Scoots," Sweetie Belle said cheerfully. "It'll take our minds of things at the very least." She slipped past where Apple Bloom was staring at the drive system to reach her pack. Digging through it, she pulled out a notebook and pencil. "Okay, ready when you are."

"Okay, first question: What's up with having fish as your cutie mark?" Scootaloo asked.

"Believe it or not, when I was young, I was actually afraid of the water. It was so bad I could barely stand taking a bath. Needless to say, I wasn't the most popular filly at school. But then one day, I met a strange half-cow thing who told me to be more assertive. I resolved then and there to face my fears. And I decided to do it in a big way. No river or pond for me. Nope, if I was going to conquer my phobia, I was going to take on the biggest bunch of water there was: the ocean."

"Just a sec," Sweetie Belle said, as she furiously scribbled down words, trying to keep up. She paused for a second, chewing on the end of the pencil, then sounded out a word. "Pho, bee, ah.. F-o-b-i-a-h. Phobia." She nodded and started to write rapidly again. "Okay."

"Turns out that when you're scared of water and never learned to swim, heading out into the open ocean probably isn't the best idea. Especially not in an area with a strong tidal current. But I got lucky. A pod of delphinia, that's scientificese for dolphin, helped me. They pushed me back to shore. Saved my life. And right then and there, I knew I wanted to study all things water related. I wasn't scared of the water anymore, and I had my cutie mark." She laughed. "Good thing those dolphins didn't leave the area. They had to save me twice more the next day."

Sweetie Belle jotted all that down.

"Also, dolphins aren't fish," Sea Swirl added.

"Told you!" Sweetie Belle hissed at Scootaloo.

Scootaloo scowled back, before turning her attention back to Sea Swirl. "And what exactly made you want to make a boat that sinks?"

"Well, I started out with regular ships, but that didn't work so well because of my seasickness. So I tried boats, and that worked better, but you can't really see underwater from them, you know? So I had them put windows in the bottom. Piece of advice, if you make a boat with windows in the bottom, don't make them openable. It can be very hard to resist the urge to brush the mane of a lionfish. Also, I don't advise brushing the manes of lio fish. Unless you want to study the biggest hives you've ever seen. Which I certainly didn't. But that's what gave me the idea: What if I could make a boat that not only went under, but then could come back up again?

"So that's when I designed the Mark I. Wasn't even a boat, really, just an upside cauldron with a thick rope attached to the top, raised and lowered by a crane. But it was a start. And that led to the Mark II, III, IV, and now the V. Which I guess might be an end. But hey, that's science. Can't unravel the secrets of the universe without breaking a few beakers."

Apple Bloom looked up from where she was working and asked a question of her own. "All this stuff can't be cheap." She circled her hoof around indicating the sub. "And then there's yer big house. How do you pay for it all?"

Sea Swirl looked up from her sketching. "Oh, my family is very rich, dating back to before the classical era. Started with some patents on some magic spells and we've built on that throughout the years with additional patents."

"How big is your family anyway?" Apple Bloom asked.

"Let me think... At our last family reunion four years ago, there were seven of us. And since then... Earthquake. Lab explosion. Lab explosion, then trampled by a marching band. Lab explosion. Labrador explosion. And bunny stampede. So just me now," Sea Swirl said cheerfully, until it hit her what she had just said. "Oh. Guess there's not much point to holding a reunion next year." Her disappointment did not last long though, as she perked right back up. "But that just means more time for science!"

"What's with this science obsession anyway?" Scootaloo asked.

Sea Swirl shrugged. "It's in our blood, I guess. We Swirls have always been fascinated with how things work. Started way back with my great ancestor Star Swirl, who was determined to unravel the secrets of growing the perfect mustache and beard, and it's been with us ever since. Sometimes it skips a generation, but something always pulls us back, be it the smell of a Bunsen burner, a desire to breed the perfect squash, or an obsessive-compulsive need to find unnamed things to name. And just look at what science has done for Equestria." She gestured dramatically with her hooves. "Why, someday science might even make it possible to banish common criminals to the moon, and not just princesses."

"Any special somepony? Because if not, Apple Bloom's brother is available," Sweetie Belle said, pushing Fruity away to stop him from nibbling on the pencil.

"Hey!" Apple Bloom snarled. "I thought we'd agreed no more trying to fix up my brother?"

"How about your favorite color?" Sweetie Belle asked quickly.

"Well, I've always been fond of puce. I know, I know. You're thinking, 'OMC, I was thinking she'd say aquamarine' or something. But I'm not a one note pony, you know. I know that for a fact because in college I was in a punk band that required the ability to play at least three chords, as well as grimace musically, so that's way more than one note. Our lyrics left something to be desired, though. It was mostly screaming."

"Aaah!" Apple Bloom screamed.

"Yup, like that."

"No," Apple Bloom said, kicking the hull in frustration. "It's this stupid drive shaft. All I've got here is wood and paper, and neither of those things will work to replace that drive band."

"Hmm… Maybe your..." Sweetie Belle started to suggest.

"Maybe my what?"

"Your bow?"

"My bow?" Apple Bloom's eyes rolled upward as she tried, unsuccessfully, to see her bow. Reaching up a hoof, she tried feeling the fabric instead. "It just might work. Sweetie, you're a genius!"

Apple Bloom quickly undid the bow from her mane. With a few twists and tugs, she got it situated in the drive system. For good measure, she gave the system one last smack. Once it was in place, she rapidly reassembled the machinery.

"That should do it."

"What about those pieces?" Scootaloo asked, pointing at several bolts and gidgets still lying on the ground.

Apple Bloom shrugged. "They probably aren't essential?"

"That's the spirit!" Sea Swirl said. "You sure your fix will hold though?"

"Well, it won't last long, but hopefully long enough for us to get to the surface,' Apple Bloom said. "Give or take a trip to the surface."

"Good job, formerly bow. Man the depth controls, and let's give it a go. Horn, keep manning the pump. Wings, let's get you hooked up to the propulsion system."

With help from Sea Swirl and Apple Bloom, the various cables and wires were quickly attached to Scootaloo. At Sea Swirl's command, Scootaloo began to slowly walk forward, powering the treadmill.

"Looks like it's holding," Apple Bloom said. "Going to start blowing the tanks."

She spun the handles, and the boat shuddered, trying to rise, but failing.

"More speed, wings," Sea Swirl ordered. Scootaloo dutifully speed up, and the shuddering increased. The boat, though, stubbornly remained fused to the lake bottom.

"Flank—"

"No!" Sweetie Belle said. "The fabric is giving it all it's got, Captain. Any more strain and it'll rip!" Seeing Sea Swirl's doubt, Sweetie Belle explained. "Trust me. I've accidentally destroyed enough of my sister's fabric to know."

"She really has," Apple Bloom said.

Sea Swirl sighed. "Full stop, wings."

"So now what do we do?" Apple Bloom asked. "We've got to break free from the mud."

"It's the suction," Sea Swirl said. "It's got us stuck like a tongue to a frozen flagpole. Not fun that, by the way. I wouldn't advise it no matter how much that barber shop pole looks like a peppermint popsicle."

"Well, what do we do now?" Sweetie Belle asked. "We can't just give up."

"Of course not," Apple Bloom said. "Crusaders never give up!"

"Just like science." Sea Swirl practically sang the last word.

Fruity chirruped his own agreement.

"Hey," Scootaloo said, "remember when we tried to be arctic explorers and the sled got stuck?"

"How could I forget?" Apple Bloom asked. "Winona wouldn't let me come within two yards of her for three weeks."

"We gotta do what we did then," Scootaloo said. "We gotta rock the boat!"

"Aren't they always telling us not to do that?" Sweetie Belle asked.

"This time is different. This time the boat needs rocking!" Scootaloo said. "Besides, there's nopony down here to tell us not to, so now's the perfect chance to see if we can get cutie marks in boat rocking!"

Sweetie Belle stopped her pumping. "I suppose it is worth a try. Certainly beats waiting down here for the air to run out."

"Okay, um, brown one, horn, ready yourself to throw yourself against the sides of the boat on my signal." Sea Swirl moved to the front of the boat and turned to face her crew. "Ready?" Sea Swirl asked. Her crew nodded. "Okay, port!" she commanded, throwing her body to the right. Her crew, however, didn't move.

"Your port or our port?" Apple Bloom asked.

"Just port. Port is always port."

"But I thought port was left, and your left is different than our left," Scootaloo said, confused.

"Not mine or yours," Sea Swirl explained. "The boat's left. Fore, port, aft, and starboard." She pointed in each direction as she said the word.

"Oh. That makes much more sense," Sweetie Belle said. "I was wondering why they used a special word."

"I think it's stupid," Scootaloo said. "How are you supposed to remember which one is left and which one is right? Why can't they just call it boat-left and boat-right, like they do for stages?"

Sea Swirl smiled. "I used to think the same thing. Such a major pain. Why, I was on the verge of coming up with my own terms. Something in Latin, I was thinking. But then this old sailor told me a handy trick. He had a peg leg, a pipe, and everything, so I knew he knew what he was talking about. And what he told me was this: 'All you need to do is remember that both port and left have four letters," Sea Swirl said, "and you'll never be confused again."

"That is handy!" Sweetie Belle exclaimed, picking up her notebook. "That's going in the article for sure!"

"Can we give it a try already?" Apple Bloom asked. "The air's starting to get a bit stale…"

"Okay, places," Sea Swirl commanded. Once everyone was ready, she called the directions. Port, then starboard, over and over. At first, the only result was a slight clouding of the water. The ponies' bodies ached from the abuse, their muscles screamed in protest at the effort, and still they kept on. When Sea Swirl's voice faltered as the boat slightly tilted to starboard, Scootaloo took over, shouting encouragement.

"Come on, once more!" Scootaloo said. "Once more and we'll be free!"

With a shout that would do a ki-master proud, the three ponies hurled themselves at the wall with all the strength they could muster. The boat lurched to port.

Their efforts paid off at last when the Mark V tilted to port and slowly began to rise, amidst water clouded with stirred-up mud.

"Engage the drive!" Sea Swirl commanded.

The battered form of the Mark V broke the surface of the lake. With a hiss of air, the hatch opened. Within, four ponies and bat eagerly breathed in the fresh air. After a brief celebration about being alive and seeing the sun again, the crew returned to work. Like a salmon determined to reach its spawning grounds, the Mark V struggled upstream, trying to return to its home.

As the doors of the dry dock slammed shut and the mooring cables were attached, the gangplank lowered. The instant it made contact with the hull, three eager fillies raced up it, eager to be back on solid ground, at least one going as far as to kiss it repeatedly. Behind them followed one unicorn mare, a fruit bat clinging to her to back, and carrying her notes from the journey. As she stepped off the gangplank, she took a look back at her submarine.

"You did us proud, Mark V," she said, offering a salute.

Almost as if it had been waiting for just that, there was a loud screech of metal tearing. Air bubbles broke the surface of the water. The Mark V listed to starboard. More sounds of metal bending, being crushed, and snapping could be heard, and the list increased. The portside flipper stuck up in the air, moving of its own accord. It almost seemed as if it were waving goodbye.

With the sound of tearing metal, the tail fell off. One of the forward view ports flew up into the air before splashing just aft of the boat. The flipper waved once more, then it disappeared, as the metal plate it was attached to came loose and sunk beneath the surface of the water. Bubbles continued to burst, so many that the water seemed to be boiling. By the time they quit, nothing could be seen of the Mark V but a pile of parts on the bottom of the dry dock.

"Guess my patch finally broke," Apple Bloom said.

Sea Swirl peered into the water and shook her head in amazement. "Well, guess it is time to starting working on the Mark VI then. Can I count on you girls to crew him when he's completed?"

"You mean go back under the water?" Apple Bloom asked.

"Where you can barely see 'cause it is dark?" Sweetie Belle said.

"And it's boring most of the time?" Scootaloo said.

"Except when it's not, because there's water pouring in," Apple Bloom said.

"Thanks to giant hydras that want to attack. Or possibly mate," Sweetie Belle squeaked.

"Meaning we could get stuck on the bottom, never to be seen again?" Scootaloo added.

"Um... yes?" Sea Swirl said.

"Sure!" the three fillies yelled out in unison. "For science!"